So far we tried different object caches with WPML and always run into issues. Therefore all our services using WPML do not have any object caches being enabled.
1) Memcached (Lite Speed Cache)
With Memcached enabled we got 404 errors on translated pages. Disabling the object cache solved this issue.
2) Redis Object Cache
With this object cache we had the same 404 errors.
Using APCu Manager we had problems seeing the latest translated content. For instance we initially translated A as A. Then we translated it to B and the text on the translated page was still A. Then we translated it to C and the text on the translated page was now B i.e. always one translation back. After disabling the APCu Manager plugin everything was fine again.
Is there a stable way to use an object cache? If yes, are special settings needed? So far all our attempts failed and all issues were 100% reproducible. We would like to use an object cache to get the best performance but there should not be any side effects.
One correction concerning Memcached: we used WP Memcached plugin from Automattic (hidden link) and not the one from Lite Speed Cache.
The issue we saw here was: German links always redirected to the English pages. This was seen in October 2022. After disabling the plugin this issue was gone.
I understand your issue and problem happening, what we can do and suggest is try to reproduce a simple example issue on a new test site with the suggested plugin from our side Redis Object Cache.
Then when we have clear steps to check, reproduce the issue, and confirm it, I can escalate further escalate to our 2nd tier and hopefully devs to check and try to fix the problem.
So please create a new clean test staging site with only WPML and Redis Object Cache. Try to reproduce the issue with clear simple steps and share those with me.
Still trying to reproduce this on a minimal system. On our large product environment and staging it is reproducible. Just got a never stopping spinner after translating which completed after disabled the Redis Object Cache.
